SEA91LA154 · Jerrell RV-4
Jerrell RV-4 · Accident: partial loss of engine power (non-mechanical) en route
From Yellowstone Airport (WYS) to Casper-Natrona County International Airport (CPR)
Event
- NTSB case
- SEA91LA154
- Event typeAccident: someone killed or seriously injured, or the aircraft substantially damaged (NTSB definition). Incident: an occurrence that affected or could have affected safety, short of that. Glossary
- Accident
- InvestigationHow far the investigation had got when the record was published: preliminary, ongoing, final or completed. Unknown where the source does not say. Glossary
- Completed
- API-reported fatalities
- 1 · all aircraft and ground
- Ground fatalities
- 0
- OperationWhat kind of flying it was, grouped by the rules it flew under: airline (US Part 121), air taxi and commuter (Part 135), general aviation (Part 91 and similar), military or government. Glossary
- General aviation
- WeatherVisual meteorological conditions (VMC): good enough to fly by looking outside. Instrument conditions (IMC): cloud or low visibility, flying by instruments. Glossary
- Visual Meteorological Cond
Jerrell RV-4
- Aircraft type
- Jerrell RV-4
- Category
- Airplane
- RegistrationThe aircraft's tail number, such as N12345 or G-ABCD. Registrations are reissued, so the same one years apart can be a different aircraft. Glossary
- N44AZ
- Operator
- Donald A. Jerrell · private individual
- Onboard fatalities
- Unknown
- Route
- From Yellowstone Airport (WYS), WESTYELLOWSTONE, MTTo Casper-Natrona County International Airport (CPR), Casper, WY
- Aircraft age
- Not recorded
- Flight rulesThe regulations the flight operated under: in the US, Part 91 (general aviation), Part 121 (airlines), Part 135 (air taxi and commuter) and others; for flights abroad, the NTSB's coarser commercial or non-commercial code. Glossary
- Part 91: General Aviation
- Phase of flightThe stage of the flight when things started to go wrong: standing, taxi, takeoff, initial climb, en route, maneuvering, approach or landing. Glossary
- En route · cruise
- First occurrenceThe single coded event the NTSB judges best describes what happened (records from 2008 on). Older records name the first occurrence in the sequence instead. Glossary
- Partial loss of engine power (non-mechanical)
- DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
- Substantial
Cause areas
- Induction air ducting › Collapsed
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
THE PILOT OF THE RV-4 EXPERIMENTAL AIRCRAFT EXPERIENCED A PARTIAL POWER LOSS, AND RECEIVED FATAL INJURIES WHEN THE AIRCRAFT IMPACTED THE WATER, DURING AN ATTEMPTED EMERGENCY LANDING, NEAR THE SHORELINE OF A LAKE. LATER INSPECTION OF THE ENGINE FOUND THAT THE SCAT TUBING WHICH RAN FROM THE AIR INTAKE FILTER TO THE FUEL INJECTOR BODY, WAS ROUTED IN A MANNER THAT CAUSED THE INTERNAL WIRE SUPPORT TO BE DISPLACED, ALLOWING THE TUBING WALLS TO COLLAPSE. THIS CONDITION REDUCED THE INDUCTION AIRFLOW TO THE ENGINE.
Probable cause
A COLLAPSED INDUCTION AIR DUCT. FACTORS INCLUDE INADEQUATE DESIGN BY THE MANUFACTURER/BUILDER, AND A MISJUDGED RATE OF DESCENT BY THE PILOT.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record SEA91LA154
- Event ID
- 20001212X17699
- Case number
- SEA91LA154
- Dataset
- historical-pre2008
- Source SHA-256
- 89e2df6d848e7ab3b42e7d7c7a03ff403303057a26ca04c95b3ea67201c3ce74
Source notes (4)
- Unreviewed is an editorial label, not an investigation status. API-sourced is not report-checked or human-reviewed. Explicit event totals are used without summing aircraft injury tables; onboard allocation is withheld. Unknown values remain unknown. The operation category is mapped from the NTSB-reported FAR part and has not been reviewed.
- Filled from the NTSB case API where the bulk record had no value: investigation status. Values present in the bulk record are kept.
- The date is the local date, which is the same as the UTC date the NTSB stores.
- API snapshot SHA-256: ddb7db1b845f522d08485c22ad2294212f9fa11601dcc2962380c96034d6b5c6; retrieved 2026-09-21T01:44:09.241Z.